


The Vast Underworld

by Maximum124 (orphan_account)



Category: Undertale (Video Game)
Genre: Eventual Romance, Eventual Smut, Non-binary Reader - Freeform, Other, Reader Is Frisk, Reader-Insert, Slow Burn
Language: English
Status: In-Progress
Published: 2015-12-11
Updated: 2015-12-14
Packaged: 2018-05-05 19:36:55
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,499
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5387759
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/Maximum124
Summary: <blockquote class="userstuff">
              <p>There's a whole world underneath the surface.</p>
            </blockquote>





	1. Fallen Down

You step through the giant stone door only to feel it shut with a loud thud behind you. You were already starting to miss the woman left on the other side.

 

At first she honestly scared you, disoriented and hurt from the fall you had taken, you heard one voice, suddenly replaced with another. Your eyes eventually focusing on this large, furry, horned monster who insisted it take care of you. The monster was intimidating to say the least, terrifying at most. But when your head stopped spinning, as she spoke more and as you noticed how gentle her eyes were-

 

Well; there reached a point where you couldn't say no, she was obviously very lonely. You ended up staying with her for a couple of nights, very thankful for the food and warm bed she provided for you. After falling underground it was just incredibly surprising to find such hospitality. Her laugh was hearty and the way she smiled when she looked at you made you feel good.

 

Even after exchanging names, Toriel kept calling you _child_. Even though you were an adult, you sort of came to the conclusion she was much older then she looked; you probably were like a toddler compared to her. Monsters weren't human, it was very possible she was ancient. 

 

You were very interested in what she had to say, she showed you her favorite books and even told you a few bad puns- when you tried to speak about the surface though she would grow quiet, or redirect the conversation. It was a reaccuring pattern you noticed quickly.

 

After awhile, it became clear though that she had no intention of letting you leave, even after you tried to make it clear to her that you needed to return to the surface. Although she pleaded with you and warned you of the dangers of the underground, _you just_ \- **couldn't**. No matter how much it broke your heart to see her alone again. Even _if_ you had no reason to return to the surface...

 

You just could not imagine a life with just her and you, sitting peacefully by the fire and making small talk until the day you died. Underground and with none of your family and friends not knowing.

 

Toriel still did not make it easy for you after all that though, the pleading turned into an argument, then a fight, back to pleading-and eventually finding yourself in her arms as Toriel gave you the most intense hug you had ever experienced up to that point.

 

Your clothes are now slightly singed from magic fire and you are out of breath from making sure singes was all you got, now stuck out in the snow- _of all things;_ _underground_. The sweat you had worked up quickly left you as you stood in the cold crisp air. You stroll forward, looking down the path laid out before you, it's dim and various trees and scrub block your ability to see very far.

 

Suddenly you don’t feel very welcome and you start to walk faster. Trudging down the snow covered path, you feel  the numbness from your feet now slowly creep up your legs. You weren't exactly dressed for the snow, it’s early fall on the surface and it didn't occur to you to put on even a sweater this morning. Hugging yourself for warmth, you kept going.

 

You almost jump out of your skin when you hear a loud _CRACK_. Looking behind you towards where the sound came from, you see a snapped twig half buried in the snow. You don’t remember stepping on it, but you must have. Your mind has been pretty preoccupied. Your plan to get back to the surface wasn’t exactly fleshed out, and now with this biting cold- you didn't really blame yourself for spacing out. You return back to your hurried walk.

 

You can't feel your arms or legs now, teeth chattering so much it began to hurt. Despite walking for a good ten minutes now the scenery around you wasn't really changing. It was beginning to worry you, maybe you should turn back, bang on that stone door and beg Toriel to let you back in.

 

As soon as that thought popped into your head a small bridge appeared in your vision. Approaching it you saw it bridged a deep gap in the ground, too long to step across by yourself but still not incredibly large. It had some sort of wooden gateway over it.

 

Your teeth stop clattering and before you could place a foot on the bridge you stop. Something inside you just stopped you from taking another step.

 

Before you could even begin try and force yourself forward, you froze in fear as you felt hot breath on the back of your neck.

**Notes for the Chapter:**

> this is gonna be a sans/reader fic, with (maybe?) smut later. I'll be adding tags and such as they apply. Hopefully future chapters will be longer. ahaha even though i had beta readers I'm still pretty nervous about posting this. Enjoy!


	2. Snowy

**Summary for the Chapter:**

> Frisk meets some new friends.

**Notes for the Chapter:**

> The more I think about walking talking skeletons, the weirder the concept becomes.

Every nerve and muscle in your body told you to run, and you did. Every single drop of adrenaline was pumped into your blood as your heart went into overdrive. Any sort of apprehension you felt over crossing that bridge disappeared as you practically leaped over it. You did not want to turn and see whatever had been standing behind you, even worse to see it chasing after you. This was terrifying. A dark forest, miles underground, filled with monsters no less-

 

You didn't feel your leg hit the rock until it was too late. Face-planting onto the ground. The earth here was covered in less snow, but whatever pain you would of felt from the fall you were saved from by your numb body. It also made it hard to stand up again, you collapsed again a few times in the process.

 

You must of run far enough for whatever was behind you to have given up, because when you finally worked up the courage to look it wasn't there. Whatever it was.

 

Shuffling forward you hug yourself again, trying to regain feeling in your hands. Hope was slowly leaving you along with all your heat, if you got one back maybe the other would follow. The trees were thinner here. As you looked around more you saw a small- what you could only assume was a wooden booth. You approached and examined it, finding inside it an empty jar and...mustard bottle?

 

You immediately drop the bottle onto the ground when you hear labored breathing approach behind you.

 

“Kinda...hooo boy...kinda rude don’tcha think?”

 

You turn.

 

It’s a skeleton. It’s talking. And apparently out of breath.

 

“Makin’ me run after you, snooping through my stuff-”

 

It’s jaw isn't moving when it talks. It’s voice is deep.

 

“C’mon, you’re working me to the bone here.”

 

It is...

 

_So small._

 

Well maybe it’s about half a foot shorter than you. The skeleton took a few more steps towards you, is this thing really what you ran from? It’s wearing such casual clothes and is surprisingly round looking. You were still apprehensive though, the skeleton did chase after you- just very slowly.

 

“Hey, you don’t look so **hot**...” It said commenting on your shivering, winking one of eye sockets as it did.

 

It finally hits you that the skeleton is making puns. Whatever sort mix of adrenaline, fear, and confusion you had just turned into laughter. You laughed, for no particular reason. It could've been out of fear for your life, maybe the cold finally got to your brain, maybe the skeleton’s pun was just that funny. The laughter mixed with the crisp air and hurts your lungs, causing you to double over and fall to the ground heaving

_You sure know how to pick ‘em lady..._

 

The skeleton mumbled something, but you couldn't hear it over your coughing. After about a minute you catch your breath and collect yourself. The skeleton monster was now standing over you and offered a gloved hand.

 

“Hey, it’s alright. I’m not gonna hurtcha.” It smiled.

 

You take its hand, as soon as you squeeze you hear a PRRPRPRPRPRPTTT come from it. You’re confused again. The skeleton gives a curt chuckle to itself and helps you stand up.

 

“My names Sans. Sans the skeleton.” He says introducing himself, shoving his hands into his jacket pockets as he did. “-And you must be a marathon runner, I’ve never seen anyone bolt that fast.”

 

You’re silent for a moment before responding. “...I’m um...s-s-sorry?”

 

Sans chuckles. “Nah I’m sorry for spooking ya, but I just needed to stop you before you went any farther. You see my brother’s up ahead-”

 

Your teeth chattering interrupts him.

 

“Oh, right.” He sighed. “You fleshy folks get cold easy, here...” Sans then sheds the blue zip up hoodie is wearing and offers it to you.

 

Slowly taking the jacket from his hands you find yourself staring at him. He really is a skeleton and not some monster with a skull-like face. The white t-shirt he was wearing under the jacket has a few small grease stains on it.

 

Sans scratches the back of his head and shifts his feet under your gaze. You just now noticed he’s wearing a pair of untied sneakers. “...Are you gonna put it on?” He asks. “Or you really dead-set on freezing?”

 

You snap out of your stare. “Oh! R-right, thank you.” The hoodie is surprisingly warm, as you slip it on you swear you can already feel the numbness ebb away. “But do-don’t you need this? I mean you must of been wearing this for a reason...”

 

Sans crosses his arms and shrugs. “Nope; consider it a welcome gift.” He doesn’t really seem to know what to do with his hands now that he doesn’t have pockets to place them in, and decides on fidgeting with the mittens he's wearing.

 

You want to argue with him, but having a warm piece of clothing on you after being out in the snow so long feels wonderful. You pull the hood over your head and zip up the front. Maybe you should question why it was warm in the first place.

 

“Anyway as I was trying to say- my brother’s up ahead. He’s kind of never seen a human before...” Sans trails off, looking over to the direction you assume his brother was. Is his brother also a skeleton? He turns back to you with a smile. “Ya know you’d probably make him really happy! Papyrus has been hunting for humans for years now.”

 

“Hunting?” You ask.

 

Sans waves his hand dismissively. “Don’t worry about it. Just know that Py’s really cool and you’d be doing me a solid by playing along with him. In-fact; consider it payment for the jacket.” He winks again. You’re not really sure how that’s possible.

 

Sans nods to behind you. “Speakin’ of the awesome devil...”

 

Turning around you see a taller and more skimpily dressed skeleton stomp through the snow towards the two of you. This must be Sans’ brother.

 

“Sans!” The large skeleton bellows. He walks right past you and addresses Sans directly. “Sans! Nice to find you actually near your post for once...” He doesn’t seem to notice you at all. “Have you seen any humans today?”

 

Sans nods. “Yep, I have.”

 

Papyrus claps his hands together. “Fantastic! Good to know you haven't been slacking off as much today!” He exclaims and turns to you. “Who's your friend?”

 

You blink in response, did he not realize you were human?

 

Sans turned towards you as well. “This is, uh- actually I never caught your name.” He said.

 

“Oh! My name’s Frisk.” You finally responded. “And you’re Papyrus right?” You said looking over at the taller skeleton.

 

“Yes, that’s me! But I mean, of course you know me; The Great Papyrus. Of whom you already know is that.” Papyrus said, the wind conveniently blows through his scarf-like cape. Or cape-like scarf. Either way it is very fashionable.

 

Papyrus eyes seem to widen when he looks down at the jacket you’re wearing. “Wowie! No wonder you’re friends with my brother, you two have very similar fashion sense! Speaking of which-” He points accusingly at Sans.

 

“Where is your jacket?! Don’t tell me you got it caught on a tree branch again and just left it!” He huffed.

 

Sans shrugs a little. “You know I don’t just **leaf** stuff behind like that.”

 

You hear a sharp clack as Papyrus’ jaw slams shut, his teeth beginning to grind. It’s easy to see he’s trying hard to hold back a smile though. Well as easy it is to see a smile on a skeleton can possibly can be.

 

He lets out a huff and straightens himself up. Sans’ soft chuckling fills the silence before Papyrus speaks again.

 

“Anyway! Break’s over! If a human is around I need to prepare! My puzzles await! Nyeheheheh!” He’s already running off back to wherever he came from cackling to himself.

 

That certainly was _something_. You turn to Sans again. “That was...uh...” It’s very hard to sum up Papyrus in a few words.

 

Sans simply gives you an understanding look in response. “Yeah he has that effect on people. You should go on ahead, you’ll find town eventually if you keep followin’ the path.” He said pointing with his thumb.

 

“There’s a town down here?” You ask surprised. The ruins were so empty, you didn’t think there was enough monsters underground to form a town.

 

“Yup. We’ve got cities and stuff too. What were you expecting?” Sans says cocking his head.

 

Honestly you weren’t expecting much, this was news to you. Everyone on the surface only spoke of monsters as if they were all dead, anyone that did believe that any still exist still only thought that they were on the edge of extinction from being forced underground. You always have had a passing interest in monsters ever since you were young, even owning a few books on them. But they always seemed unreal, just the subjects of fairy tales and folklore. It just sort of finally all clicks for you, that you’re deep underground, underneath the seal, and you’re having a surprisingly pleasant conversation with a monster.

 

The ruins were so empty and quiet, you just expected the rest of the underground to be like that.

 

Sans snaps his boney fingers at you. “Hey kid, you alright? Don’t go tellin’ me you’re still cold...”

 

You shake your head. “I’m fine.” You reply. You really are, you stopped shaking and regained feeling in your limbs awhile back.

 

“Good.”

 

He begins to walk off in the direction papyrus ran off to, you notice small clouds leaving his nose periodically. He’s a skeleton, he couldn’t possibly be breathing, right? You follow him shortly after, seeing him round a corner and just seemingly disappear. Giving a quick onceover to the tree he retreated behind his footprints just seem to vanish.

 

He must of run ahead, which would be a shame because something inside of you would've liked to walk with him.

 

The snow crunches satisfyingly underfoot, the white landscape is so much more enjoyable when you’re not freezing to death.

**Notes for the Chapter:**

> Its longer! There's a lot of dialog though and its basically just recounting the game, hopefully next chapter I can start departing from the games narrative. I'm not a writer by trade so if stuffs a little wonky I apologize, I didnt have any beta readers for this chapter


End file.
